DE1571359A1 - Refractory cast iron bodies - Google Patents

Description

DR. JUR. DIPUCHEM. WALTER BEfI LEGAL LAWYER IJHO NOVARE

DR. JUR. DIFL-CHiM. H.-J. WOLFP
DR. JUR. HANS CHR. Ax

ISECHTSANWXlTe

623 FRANKFURT AM MAlN-HOCHST

U ^^ IRNOV.

Our no. 11 987

Corning Glass Works Corning, N.Y., V.St.A.

Fireproof fusible cast bodies

The invention relates to refractory ceramic castings which by melting refractory ceramic material and pouring the molten material into a pre-formed mold Br rigid can be obtained into a monolithic cast body. More particularly, the invention relates to novel carbon / carbide refractory fused castings having superior resistance to thermal shock Resistance to corrosion and erosion by the ferrous lime slags in a reducing atmosphere like them normally occurs in the basic oxygen steel manufacturing process, e.g. the LD or Stora-Kaldo process. the Slags usually have a lime-silica ratio VO * IM to 1.5M in the early stages of warming, and this one Ratio increases to over 2.5: 1 towards the end of heating

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for the lime-rich end slag. The reducing atmosphere tends to consist mainly of carbon monoxide.

It is known that brittle masses of metal carbides (e.g. titanium carbide, zirconium carbide, etc.) can be produced by using suitable raw materials at elevated temperatures which the material melts completely or imperfectly. These fragile masses are in situ in the. electric furnace used to make them. The masses are later crushed to a granular mass, which is used as emery or according to known Process (but without complete melting and solidification to form a monolithic cast body) to produce highly refractory bodies . reconnected for various high temperature applications. Also, brittle masses of molten metal carbides have been produced from raw materials containing excess carbon in some cases, so that free carbon appeared in these masses, but efforts mostly went to avoid such free carbon in the granular materials, because it made the production of suitable shearling material difficult or reacted with a carbide-forming element during the combination to form a carbide-bonded body. Fused cast bodies have not yet been produced which essentially consist of metallic carbide crystals and a decisive amount (i.e. at least 5% by weight) of free carbon (Graphite), which penetrates the essentially randomly oriented metal carbide crystals. As a result, were also never recognized the great technological advantages that can be achieved here, namely the greatly superior durability against heat shock and the greatly superior resistance to slag corrosion and erosion in basic oxygen steel making furnaces.

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There is an ever increasing need for materials that withstand high and sudden temperatures. There were now melt casting compounds with a novel composition and structure found that are suitable to meet this need. A The aim of this invention is therefore to produce highly refractory Castings made of refractory metal carbide / carbon ~ Angled cast material that has thermal shock resistance, which of the previously known refractory cast iron bodies is superior.

Although the popularity of the basic oxygen steel manufacturing process steadily increasing, represents the relatively rapid wear and tear of the lining used in these basic oxygen furnaces refractory material is a major obstacle on the way to greater economy and higher yields. It it has now been found that this problem is largely alleviated can be that one of the linings of the basic oxygen furnaces from the new carbide / carbon melt casting masses of the present invention which have resistance to slag corrosion and erosion, the that of the refractory masses previously used for the linings is far superior. Another object of the present invention is therefore the production of refractory cast iron r bodies with superior slag resistance in a reducing atmosphere, and for use as the lining of basic oxygen ovens or vessels. The invention Cast bodies are particularly suitable for the production of factory linings in the pear-shaped basic oxygen vessels, which usually consist of a pear-shaped metal tank or -housing, one covering the inner surface of this tank insulating refractory lining and a covering the inner surface of this insulating refractory lining refractory lining, as well as devices for

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Blowing an oxygen train into the refractory lined Tank exist.

The subject matter of the present invention can broadly as a refractory cast iron can be referred to, which consists of at least 5% by weight free carbon, which is essentially randomly oriented metal carbide crystals interspersed and locked together, and contain the cast bodies in addition to carbon, at least 20% by weight of metal carbide-forming Substances, as explained in more detail below. Although these are the only two essential analytical components are the cast body, other analytical components may optionally be included depending on those used Raw materials, the manufacturing conditions and the desired properties of the end product.

Although a lower limit of 5% by weight for the required free carbon was given in the previous section in order to achieve better technical and industrial results, this limit can also cover some fusion castings which have only slightly improved thermal shock resistance, and in which the free carbon is present as a layer pattern or in platelets between metal carbide crystals. The present invention therefore particularly relates to such refractory »melt cast products which contain at least 11% by weight (and preferably 20 %) free carbon in the form of a random and disjointed intermediate structure which penetrates and locks the essentially randomly oriented metal carbide crystals. This latter characteristic is typical of melt castings having excellent thermal shock resistance, among other desirable properties.

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The process for producing the cast bodies according to the invention consists in heating a carbon-supplying material with metal carbide-forming materials and / or metal carbides formed therefrom in a furnace and this heating carried out at a temperature high enough to melt a substantial amount of the raw material and also a reaction between bring about all of the metal carbide-forming material and the carbon. The composition of the raw material, the nature of the atmospheric sphere in contact therewith, and the heating time and temperature are selected so that the molten mass formed consists of: (i) carbon and metallic elements in an amount such that the cast product , contains the minimum of free carbon and metal carbide-forming substances specified in the preceding sections, (2) of metallic elements of a first group specified below in an amount that the melt-cast product contains at least 10% by weight of these elements, (3) of oxygen and / or nitrogen in an amount that the melt-cast product analytically contains a total of at most 0 to 15% by weight of both together, but of each not more than 10%, and (k) from a remainder, if any, which analytically from 0 to 5 wt -.% of other elements or impurities · Finally, the molten mass into a mold ge poured to form a molded body having the structure and composition given above. It is believed that the relatively faster solidification and cooling that occurs with these casting processes (as opposed to the slower solidification and cooling that occurs when a large monolithic mass is formed in situ in the furnace where the melting took place ), at least in part for the unique structure of randomly oriented metal carbide crystals with a random and disjointed intermediate structure of free carbon that permeates and displaces these crystals

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lock, let responsible. These new results are available in the In contrast to the in situ solidification of such materials, such as boron carbide / carbon compositions Formation of brittle bodies, which have a predominantly layered pattern of platelets made of free carbon, which forms an intergrain structure between highly oriented (elongated and parallel) carbide crystals.

The analytical metal carbide-forming substance can be composed of one or more of the metallic elements described below exist. If only a single metallic element is used to form the carbide crystals, that element is Titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molyb-, dan or tungsten. Any mixture of two or more of the above metals can also form one or more Carbide phases are used, depending on the degree of alternating, mutual solubility of one carbide in the other carbide or the other carbides. The metal carbide-forming substance can also consist of mixtures of one or more of the above Metals of the first group with at least one metal of the subsequent second group, namely silicon, manganese, iron, Cobalt or nickel exist, provided that the metal content of the first group in the Gußköm does not fall below 10% by weight. In the case of such mixtures, too, one or more metal carbide phases are formed formed, depending on the degree of mutual solubility of one carbide in the other carbide or carbides.

The other analytical components which may be permitted in the cast bodies according to the invention can be referred to as diluents and / or impurities ; Oxygen and nitrogen are given here as diluents , although in some ferrous metals they must be regarded as impurities, while in other cases they are desirable additives. Both oxygen and nitrogen are said to be analytical

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Do not exceed 10 wt .- # of the cast body and the total amount of oxygen plus nitrogen should not exceed 15 wt .- # of the cast body. The cast bodies can also analytically contain up to 5% by weight of impurities. Such impurities usually result from the use of less pure starting material and consist of aluminum, alkali metals, alkaline earth metals, rare earth metals, sulfur and phosphorus.

For a more detailed explanation of the invention, reference is made to the figure which is a photomicrograph of a typical microstructure in accordance with the present invention.

In contrast to pure silicon carbide material, this can be refractory Material of the present invention easily without excessive sublimation such as occurs when melting silicon carbide, be melted. This is due to the significantly lower vapor pressure of the carbide materials used according to the invention. the Raw materials are preferably either a mixture of the corresponding metal carbides and carbon or graphite, or a mixture of the corresponding metals and / or metal oxides and an excess amount of carbon to form of the corresponding carbide and free carbon (graphite). These mixtures can either be in a conventional electrical Arc melting furnace using graphite electrodes, or in an electric induction melting furnace below Can be melted using a graphite liner or a graphite insert. To avoid excessive oxidation of the approach Appropriate measures must be taken to prevent the ventilation air from occurring to cover the approach during the entire heating process, for example by maintaining a neutral or reducing atmosphere above the surface of the load, or by applying a loose Lid on the top opening of the furnace. It is preferred that

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To provide preparation materials before loading the furnace, and when mixtures of metals and / or metal oxides are used it may be necessary to agglomerate the batch mixture into pellets before loading it into the furnace. Without these Agglomerization occurs imperfect melting and separation leaving an excessive amount of free metal and oxides in the melt. The pellets are said to be so high be heated so that conversion to the carbides, but no melting occurs, in order to reduce the consumption of electricity to keep economic limits and to reduce the evaporation of batch materials. If the gas evolution and Flame formation largely subsided, are the batch materials melted in the same way as the original carbides and carbon batches, to form a Molten bath, which is surrounded by a mass of unreacted batch materials, one against contamination of the weld pool represent a protective lining. Part of the carbon content of the molten product comes from the graphite electrodes or the graphite liner, and therefore the amount of carbon in the batch is kept lower than the amount required to achieve a desired composition.

An exact prescription for the composition cannot be given, since the amount of carbon from each of the two Sources depends on such factors as time, temperature, etc. In any case, the appropriate ratio can be determined by a specialist can be determined by a minimum of preliminary testing.

After an adequate amount of molten batch material has been formed, the molten mass is poured into a graphite mold, which is surrounded in a customary manner by GlUhpulver such as aluminum powder, powdered coke, etc., and is

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allowed to solidify therein to form a monolithic cast body made of refractory melt casting material, which has the shape of the casting mold. This process leads to a relatively rapid solidification and to arbitrarily shaped carbide crystals which are largely (i.e. at least 40% by weight of the crystals) oriented randomly and which have a medium to fine grain size. The free carbon, which in most cases is crystalline graphite, forms a random and incoherent interwoven pattern and permeates the carbide crystals. In many cases the free carbon or graphite is linked in an interlocking manner which is typical only of fused cast refractories. The microstructure of the cast bodies according to the invention is better illustrated by the figure. This microstructure is that of Example 15 of Table I. The light areas 10 are the randomly shaped and oriented zirconium carbide crystals. The random and incoherent interwoven pattern or structure of free carbon (graphite) can be seen in the dark areas 12. Crystal bonding occurs between graphite and graphite 18, carbide and graphite 16 and carbide and carbide 14. In many cases, the carbide-graphite bonds form irregular interfaces of an interlocking nature, as can be seen at 20. The large graphite areas 22 consist of primary graphite that has formed between the carbide crystals, and the smaller graphite areas 24 appear to be eutectic or consist of exuded (filled) graphite within the carbide crystals. Sometimes the smaller areas of graphite are dendritic in shape. The following example explains the practical implementation of the invention and the results achieved. A finely comminuted batch mixture was produced which consisted of 60% by weight of Il "eniter" and 40% by weight of graphite of electrode quality. D44 XlMeniters had the following analytical composition i «·· ¥ .-%! 63.14 TiO ₂ , 31.7 Pe ₃ O ₃ , 0.5 Al ₂ O ₃ , 0.4 MgO, 0.3 SiO ₂

..- ', - *.,. . 109812/1307

ORIGINAL INSPECTED

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0.12 Cr ₂ O-. A small amount of water and starch were added to the mixture and then agglomerated into small pellets. The pellets were placed in an electric arc furnace which covered the lower ends of the braphite electrodes with graphite foreshortening rods between them. A loosely fitting graphite lid was placed over the furnace chamber and the electrical current / was switched on to such an extent that the batch materials reacted with one another without, however, noticeable melting. The beginning of the reaction could easily be recognized by the evolution of gas and the appearance of flames at the openings in the graphite lid. After the flame and gas evolution had largely subsided, the current was increased to melt a substantial portion of the converted charge, sufficient to fill a graphite form of brick shape measuring 7.5 x 11.5 x 33 cm and the usual core mark . The furnace was tapped and the molten material quickly poured into the mold, which was surrounded by aluminum glow powder. The top of the core mark was also covered with aluminum powder and the mold was allowed to stand until the goat-shaped casting had cooled to room temperature. The casting had the following chemical analysis (wt%) i 54.0 titanium, 17.3. Iron, less than 1 metric tons of oxygen, the remainder being carbon. The X-ray analysis of the casting revealed as the predominant phase of TiC with a smaller amount of Eisencarbidkristallen, and a graphite intermediate structure represented by the set Car bidkristalle. The graphite was determined to be in excess of 5 parts by weight of the cast body.

The greatly superior thermal shock resistance of the above example was demonstrated by cutting a sample approximately 2.5 × 1 × 8 × 1.2 cm from the cast body, heating it to 180 ° C. and then throwing it into room temperature hater * Da · is ! a cyolus of this severe test. In the present case,

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the test cycle was repeated five times without any noticeable breakage due to thermal shock. Another sample of the same casting and of the same size was subjected to three test cycles with no appreciable thermal shock fracture. The results obtained with these samples according to the invention can be compared with the results obtained with a commercially available hot-melt casting compound which had the highest degree of heat resistance to date. This latter fused cast composition consisted of (wt. Another melt casting compound, which was previously well known for its resistance to severe thermal shock, consists of pure magnesium oxide melt casting with a crystalline structure of at least 75 % by volume of uniform, unoriented periclase crystals, the majority of these crystals being fine to medium Has grain size from 20 to 5000 microns. Samples of the same size of these magnesia castings shattered into two or three pieces on the first or second cycle of the thermal shock test described above.

About the improved slag resistance of the castings according to the invention in the reducing atmosphere of the basic oxygen steelmaking process To demonstrate the following experiment with samples according to the invention and with samples conventional materials, two of which are commonly used for lining basic oxygen furnaces. The test consisted of placing 3.5 by 2.5 by 1.2 cm samples in a gas-oxygen oven in which the Temperature and the reducing atmosphere of a basic oxygen furnace could be mimicked. Were at 1700 C. the samples for two and a half to three hours, with one of their largest surfaces facing up, by a falling one Stream of molten lime-rich, basic,

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seniferous slag droplets are moved through at a constant speed of 60 times / h. The slag corresponded to the basic oxygen furnace slag that developed during steel production and had the following composition (% by weight): 23.75 ^Fe ₂ ° 3> ² 5.94 SiO ₂ , 40.86 CaO, 6.2 5 MgO and 3.20 AlpO, · A " ¹ At the end of the test, the average thickness of the sample was measured and compared with the original thickness of 1.2 cm before the test. The results were expressed as a percentage change in thickness (referred to as percent slag wear). three samples of the above-described titanium carbide / carbide / graphite cast body of the slag abrasion was 17-3 5%> in contrast, efh commercial teergebundener dolomite bricks showed a slag abrasion of 100% (that is, the sample was completely into two parts cut.) samples of common Basic fused cast masses made from mixtures of 55% magnesite and 45% chrome ore show slag abrasion of 50 to 100% Resistance in reducing atmospheres is advantageous in addition to recently developed basic melt casting compounds for basic oxygen furnace linings. These latter refractories are molten and cast mixtures of 90 wt .- # magnesite and 10 wt .- # rutile and show a slag resistance of 25 to 30 % in the test described above. The behavior of graphite (electrode quality) in this test is also interesting. A series of 10 samples of graphite showed slag wear of 24 to 45 %

The previously sewn titanium carbide / iron carbide / graphite castings also showed adequate resistance to attack by molten iron. A sample of the way in which they had been used in the above-described slag resistance test was immersed for half an hour in molten iron of 175jO ° C. The molten iron abrasion was 19 % and it is known from experience that there was iron abrasion in this test

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of 20 % or less is indicative of adequate resistance to corrosion from molten iron.

The titanium carbide / iron carbide / graphite castings have other remarkable properties as well. Their modulus of rupture (bending) at 1340 ° C is 140 to 420 kg / cm. Samples of these castings showed at 2200 ⁰ C under a compressive load of 1.76 kg / cm, no significant deformation (ie, less than 5%). The cast body also have a rather low for such a highly refractory Schmelzgußmassen coefficient of thermal expansion, namely less than 85 χ ^10/0 C at 1000 ⁰ C.

The harmful effect of excessive amounts of impurities became evident during the production of further castings from the above-mentioned mixture of 60% by weight ilmenite and 40% by weight carbon, when one of the castings was contaminated with aluminum glow powder during casting. The chemical analysis ■ was as follows (in% by weight): 47.8 titanium, 16.2 iron, 8.8 oxygen, 9.8 aluminum, the remainder carbon. The corrosion resistance to molten lime-rich basic slag and ge ¹ -molten iron was very poor, and samples of this material disintegrated just standing on the shelf within a short time.

Further examples of batches which can be melted to form cast bodies according to the invention are listed in Tables 1, 3, 5 and 7 to further explain the invention. Most of these examples · melted satisfactorily in an electric induction furnace "The examples 1O ₉ 11? 17, | β ₉ 26, 31? 43, 73 and 89 represent typical examples of _4C & @ he Aaaitse dfe _s di © sufsdedesistelXead ± a-an electric

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BATH ORIGINAL

Up to as described above * All compositions and analytical values in these four tables and in Tables 2, 4, 6 and 8 are given in% by weight. Typical examples of batch materials have the following chemical analysis (in% by weight ) t

Ti (titanium sponge)

99.3 f> Tl, 0.40 % max. Mg, 0.1 % max. Pe, 0.15% max. Cl. TiO ₂ (rutile)

96-98 % TiO ₂ , 1 % max.Pe ₃ O ₃ , 0.3 % ZrO ₂ , 0.3% Al ₃ O ₃ , 0.25 f> SiO ₂ , 0.1% Cr ₂ O ₃ , 0 , 29 # V ₂ O ₅ , 0.025-0.05 % P ₂ O ₅ , 0.1 % S.

TiN (titanium nitride)

99 + % TiN. Zr (zircon sponge)

99.2 % min. Zr + Hf (Hf about 2 %) , 0.2 % max. Cr + Pe. ZrO ₂ (zirconium oxide)

94.15 % ZrO ₂ , 2.00 % HfO ₂ , 1.00 % max. Al ₃ O ₃ , 0.8 % max. SiO ₂ , 0.75 % max. CaO, 0.50 % max. Fe ₃ O ₃ .

97 + % HfO. (Zr about 2 %) *

812/1307 BATHROOM

* 99 +

Nb ₃ O ₅ (optical quality) 99.9 +

Ta ₂ O ₅ (optical quality)

99.9 + % ^Ta 2 ° 5 Ta (high purity metal)

99 + % Ta.
Cr ₂ O ₃ (green chromium oxide) 99.75 + % Cr ₂ O ₃ .

Mo (high purity metal)

99 + % Mo.
W (high purity metal) 99 + % W.

WO ₃ (Scheclit concentrate) 68-72 % WO ₃ (remainder probably CaO) ₁

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Fe (pure metal) 99 + % Fe.

FeTiO ₃ (Ilraenite)

(as described above) Cr (pure metal)

99 +% Cr. Si (pure metal)

99 + % Si. Mn (pure metal)

99 +% Mn. Hf (pure metal) 99 + % Hf.

ZrSiO, (zirconium ore)

67.23 % ZrO ₂ (HfO ₂ approx. 2 %) , 32.40 % SiO ₂ , 0.18 % FeO, 0.18%

V (pure metal) 99 + % V.

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Nb (pure metal)

99 +% Nb.
TC * O. (Transvaal chrome ore)

43.77% Cr ₂ O _3, 23.28% FeO + Pe ₂ O _3, 13.00% Al ₂ O ₃ 11.79% MgO, 3.24 f SiO _2, 0.5% CaO, 0.4 % TiO ₂ ,

Table 11

Composition of the phase analysis%% heat ^ Batch mixture "slag iron shock

kenab- abrasion cycle No. rubbed ⁺ *

1 85% Ti, 15% C. 84.0%
% G TiC , 16.0 7 - - 2 80% Ti, 20% C. TiCx > 5% G 11 > 8 3 75% Ti, 2 5% C. 81.0%
% G TiC _: , 19.0 2 .— - 4th 70% Ti, 30% C. TiC,> i > 5% G 14th - 5 60% Ti, 40% C. TiC, >> * 5% G - > 8 6th 40% Ti, 60% C. TiC,> 5 > 5% G - - 7th 65%
15% Ti,
C. 20% TiO ₂ , TiC,> 5% G - 4th 8th 49%
21% Ti,
C. 30% TiN, TiC,> ^ . 5% G - -

9 75% TiO ₂ , 25% C TiC, »5% G, CC Fe -

10 40% TiO ₂ , 60% C TiC,>:> 5% G -

11 70% Ti0 ₂ , 30% coal TiC, 2κ 5% G, TiO ₂ -

12 88% Zr, 12% C 84.5% ZrC, 15.5% 20 26:

13 83% Zr, 17% C ZrC, »5% G - 7

14 75% Zr, 25% C 85.7% ZrC, 14.3% 29 ^ 7

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Table 1 (continued)

No. composition
of the approach
mix Phase analysis ⁺ %
Slack
kenab-
rubbed *
Bisen
abrasion Heat-
shock-
cyclen 15th 60% Zr, 40% C ZrC, ^ 5% G. > 8 16 50% Zr, 50% C 62.5% ZrC, 37.5
% G - - 17th 50% ZrO ₂ , 50% C ZrC ^ fc. 5% G - - 18th 77.4% ZrO ₂ ,
22.6% coal ZrC,> 5% G, ZrO ₂ - - 19th 81% HfO ₂ , 19% C Hf C, * 5% G - - 20th 77.5% HfO ₉ ,
22.5% C 90.1% HfC, '-
9.9% G. - - 21 70% V ₂ O _5, 30% C VC, ^ 5% G. - - 22nd 77.5% Nb 0,
22.5% C ^{Α 5} NbC, 2 * 5% G. - - 23 66% Nb ₉ O,
34% C ^{d 5} HbC, »5% G. - - 24 70% Ta ₉ O.,
30% C * ° TaC, ** 5% G. - - 25th 76% Ta, 24% C TaC,> 5% G. - - 26th 50% Cr ₂ O ₃ ,
50% C Cr ₃ C ₂ , Cr ₇ C ₃ ,
^> 5% G. - - 27 80% Cr ₉ O-,
20% C ^J Cr ₃ C ₂ ,> 5% G. - - 28 60% Mo, 40% C MoC, Mo ₂ C,
»5% G __ --- 29 70% Mo, 30% C MoC,> 5% G. - - 30th 80% W, 20% C WC ^> 5% G - - 31 50% WO ₃ , 50% C WC, W ₂ C, »5% G -

The symbol G denotes a graphite phase.

The symbol> indicates d & B the test after the specified Number of cycles was interrupted without breaking occurred.

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BAD ORiGlNAj.

The values in Table 1 are indicative of single metal carbide / graphite compositions, and it can easily be seen that an amount of at least 5% by weight free carbon (graphite) in the microstructure for superior thermal shock resistance leads. The titanium carbide / graphite samples were particularly resistant to corrosion by molten slag and Iron. The zirconium carbide / graphite samples do not show the same corrosion resistance as the titanium carbide / graphite samples, however, they are sufficiently resistant to slag corrosion. As mentioned earlier, does not come the entire carbon content of the cast body from the batch mixture, but part of the graphite electrodes or the Graphite container. The chemical analysis in the table shows this very clearly. These values, together with those of Table 1, also give a good indication of the composition of the Mixture that is required to achieve a certain desired composition of the cast body.

Table 2:

No Actual Analysis Calculated

analysis

1 66.5% Ti, 33.3% C, 0.2% Fe 67.2% Ti, 32.8% C

2 69.5% Ti, 30.4% C, 0.1% Pe

3 64.8% Ti, 3 5.2% C

12 79.0% Zr, 21.0% C, 74.7% Zr, 25.3% C

13 66.5% Zr, 33.5% C

U 76.0% Zr, 24.0% C

15 76.0% Zr, 24.0% C

16-55.2% Zr, 44.8% C

20-84.4% Hf, 15.6% C

⁺ Based on the phase analysis in Table 1 and assuming that there is no excess carbon in solid solution in the carbide phase.

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The examples given in Tables 3 and 5 are typical of those compositions which contain two carbide-forming metallic substances, which leads to the formation of one more carbide phase, as can be seen from Tables 4 and 6 . These values also confirm the fact that at least 5% by weight of graphite leads to a superior thermal block resistance in all cases, in contrast to those samples which contain less than 5% by weight of free carbon. Although not all samples have superior resistance to molten slag and iron, the titanium / iron / carbon samples, titanium / zirconium / carbon samples, and zirconium / chromium / carbon samples are particularly well known highly corrosion resistant to molten slag and iron. The titanium / iron / carbon samples of Table 3 clearly show that a suitable ceramic casting material for linings of basic oxygen furnaces can be made from such relatively inexpensive raw materials as ilmenite and graphite. The inclusion of iron in the composition also reduces the melting point of the mixture and makes the cast body more machinable without sacrificing its superior properties. While the approximate melting point of a mixture of 80% Ti and 20% C is more than 3000 ° C, the approx. ₁ Fe melting point of 65% Ti-15% Fe-20% C2 50O ⁰ C. With regard to the iron-containing samples It should be noted that a considerable amount of iron is lost during the smelting process, as can be seen from the chemical analyzes in Table 4. These values are a good indication for the development of a batch mixture which leads to a suitable analysis according to the invention.

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Table 3:

No. Composition of the batch mixture Heat

32 7 5% Ti, 5% Fe, 20% C

33 70% Ti, 10% Fe, 20% C

34 65% Ti, 15% Fe, 20% C 3 5 60% Ti, 20% Fe, 20% C

36 50% Ti, 30% Fe, 20% C

37 40% Ti, 40% Fe, 20% C

38 60% Ti, 10% Fe, 30% C

39 52.5% Ti, 17.5% Fe, 30% C

40 40% Ti, 20% Fe, 40% C

41 44% Ti, 12% Fe, 44% C

42 80% FeTiO ₃ , 20% C

43 50% FeTiO ₃ , .50% C

44 80% Zr, 10% Fe, 10% C

45 83% Zr, 5% Fe, 12% C

46 63% Zr, 25% Fe, 12% C

47 48% Zr, 40% Fe, 12% C

48 53.5% Zr, 6.5% Fe, 40% C

Slag Bisen shock- abrasion abrasion cyclen ■ WIM 4th 4-18 26th > 8 - - 5 21 - - - - 5 35 - - 21 20th - - - 8th 22nd 22nd - - - > 8 5

16
20th
100
35

The symbol> means that the test is after the specified number of Cyelens was interrupted without breakage occurring.

Table 41

No. phase analysis *

.JU.

83.2% TiC, 2.3% PeC. 14.5% G ^xy

71.5% TiC, 7.4% Fe C, 8.7% G ^xy

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67.4% Ti, 30.9% C, 1.7% Fe 67.5% Ti, 31.5% C, 1.0% Fe

61.4% Ti, 34.4% C, 4.2% Fe

Table 4 (continued)

No. phase analysis " ¹ "

Chemical Analysis

55.0% Ti, 38.4% C, 6.6% Fe

58.0% Ti, 34.8% C, 7.2% Fe

43.5% Ti, 43.6% C, 12.9% Fe

TiC, Pe C i χ y

C, OC Fe

⁺ The symbol G denotes a graphite phase. ⁺⁺ Real values.

Table 5 »

No. Composition of the batch mixture

Slag abrasion Iron abrasion

Heat-

shock-

cyclen

49 63% Ti, 10% Zr, 27% C

50 56% Ti, 20% Zr, 24% C

51 32% Ti, 52.8% Zr, 15.2% C

52 8.0% Ti, 79.2% Zr, 12.8% C

53 20% TiO ₂ , 70.4% Zr, 9.6% C

54 30% TiN, 61.6% Zr, 8.4% C

55 52.5% Ti, 25% Cr, 22.5% C

56 63% Ti, 10% Cr, 27% C

57 44% Ti, 15% Gr, 40% C

58 3 5% Ti, 50% Cr, 15% C

59 79.2% Ti, 1% Si, 19.8% C

60 77.6% Ti, 3% Si, 19.4% C

61 79.2% Ti, 1% Mn, 19.8% C

62 77.6% Ti, 3 * Mn, 19.4% C

63 30% Ti, 40% Hf, 30 * C

64 15% Ti, 60% Ta, 25 * C

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- 6th - 6th 12th __ 100 7th 51 3 100 18th 15th - »-

> 8

> 8

> 8

> 4> 4

Table 5 (continued)

No. · Composition of the batch mixture

65 40% Ti, 30% W, 30% C

66 81% Zr, 8% Cr, 11% C

67 73% Zr, 15% Cr, 12% G

68 63% Zr, 25% Cr, 12% C

69 81% Zr, 8% Si, 11% C

70 72% Zr, 10% Si, 18% C

71 69% Zr, 20% Si, 16% C

72 48% Zr, 40% Si, 12% C

73 50% ZrSiO ^, 50% C

74 81% Zr, 8% Mn, 11% C

75 20% Zr, 50% Hf, 30% C

76 60% Zr, 10% V, 30% C '

77 30% Zr, 40% Ta, 30% C

78 40% Zr, 30% W, 30% C

79 35% Hf, 40% Ta, 25% C

80 20% Nb, 50% Ta, 30% C

81 76% Cr, 5% Fe, 19% C

82 3 5% Mo, 40% W, 2 5% C

83 5% Mo, 70% W, 2 5% C

%% Heat slag iron shock abrasion abrasion cyclen

14th - - 24 - - 11 - - 24 , -, - 10 6th 22nd 7 · 21 13th

20th

The symbol means that the test according to the specified Number of cycles was interrupted without breakage occurring.

109812/1307

Table 6:

No phase analysis Chemical analysis

55 (Hf ₁ Ti) C,:> 5% G. co / f \
O / o Va CQ (Ta, Ti) C, ^ 5% G. po
63 (Ti, W) C, (W, Ti) C, ^ 64 ZrC, SiC,> 75% w 5% G 65 (Hf, Zr) C,? - 5% G 73 (V, Zr) C, (Zr, V) C, ^ 5% G 75 (Ta, Zr) C,> 5% G 76 (Zr, W) C, (W, Zr) C, ^ 77 (Ta, Hf) C, 5-5% G. + 78 (Ta, Nb) e, ^ 5% G "Of O 79 94.4% Cr ₃ C ₂ , 5.6% G 80 (W, Mo) C, (Mo, W) C,>! 81 (W, Mo) C, > 5% G. 82 83

49.6% Ti, 21.5% Cr, 28.9% C, 34.3% Ti, 46.3% Cr, 19.4% C

⁺ The symbol G denotes a graphite phase. ⁺⁺ Actual values.
+ Traces of iron in solid solution in Cr ₃ C ₃ .

The examples shown in Table 7 illustrate some of the complex ones Combinations of carbide-forming metals that can be used in the cast body according to the invention, and the in many cases produce complex solid solution carbide crystals in the cast bodies as shown in Table 8.

109812/1307

Table 7:

No. Composition of
Approach mixture %
Slag
abrasion %
iron
abrasion Heat-
shock-
cyclen 84 49% Ti, 20% Cr, 10% Fe
21% C 29 13th - 85 42% Ti, 30% Cr, 10% Fe,
18% C 68 27 - 86 55% FeTiO-, 30% T.CO ,,
15% C * - - - 87 40% TiO ₉ , 3 5% T.CO.,
2 5% C * - - - 88 30% TiO ₉ , 45% T.CC,
2 5% C * - - - 89 30% TiO ₀ , 10% T.CO.,
60% C * - - - 90 52.5% Ti, 5% Cr, 20% Mn,
22.5% C - - 5 91 59.9% Ti, 10% Zr, 5% Fe,
2 5.5% C 29 - - 92 56% Ti, 10% Zr, 10% Fe,
24% C 21 - - ' 93 49% Ti, 20% Zr, 10% Fe,
21% C 32 - - 94 56% Ti, 10% Zr, 10% Mn,
24% C - - S 8 95 59.5% Ti, 5% Zr, 10% Mn,
2 5.5% C 31 - - 96 49% Ti, 10% Zr, 20% Mn,
21% C 39 - - 97. 5% Ti, 20% Zr, 20% Hf, 20% Ta, - ■ MW

5% C

The symbol ^ means that the test is interrupted after the specified number of cycles became without breakage occurring.

EC

IN-LAW

109812/1307

Table 8:

No phase analysis ⁺

86 (Ti, Cr, Fe) C, ^ 5% G, OC Fe

87 (Ti, Cr, Fe) C, ^ 5 # G

88 (Ti, Cr, Fe) C, χ5 # G

89 (Ti, Cr) C, 1 ^ 5% G, OC Fe 97 (Zr, Hf, Ta, Ti) C, ^ 5% G.

⁺ The symbol G denotes a graphite phase.

Ze & rr require Güßkörper the invention only analytically 20 wt .- # metallcarbidbildenden of substances (as indicated above), but were preferred for the individual metals, and determines optimal minimum values with which they can be used alone or in certain combinations.

These values are (in% by weight):

Preferred optimal

Titan alone 40 69 Zirconium alone 40 65. Hafnium alone 45 60 Vanadium alone 40 65 Niobium alone 40 55 Tantalum alone 45 60 Chrome alone 40 55 Molybdenum alone 40 55 Wlfram alone 40 60 Titanium iron 30-0.1
(40 total) 40-5
(60 total>) Titanium zirconium 1-1
(40 total) 2 5-25
(60 total)

109812/1307

Zirconium-Iron Zirconium-Hafnium Zirconium-Chromium Zirconium-Silicon Mob-Tantalum Molybdenum-tungsten Chromium-iron Ti tan-chromium-iron

10-0.1
(40 total)

0.1-0.1
(40 total)

10-0.1
(40 total)

20-0.1
(40 total)

0.1-0.1
(40 total)

0.1-0.1
(40 total)

0.1-0.1
(30 total)

30-0.1-0.1
(40 total)

40-5
(45 total)

5-5
(60 total)

2 5-5
(50 total)

30-5
(60 total)

5-5
(55 total)

5-5
(55 total)

13-5
(40 total)

30-5-5 (60 total)

The total content of oxygen plus nitrogen should be 10% by weight not exceed, but optimum corrosion resistance to basic oxygen furnace slag is then obtained, w if this total content is reduced to a maximum of 5% by weight and preferably 1% by weight. A reduction in impurities up to a maximum of 1% by weight also contributes to the achievement optimal results.

Although the term "alloy" in its usual sense refers to such Substances that consist of two or more metals are used, which were dissolved in one another in the molten state and then solidified, can because of the similar or analogous The nature of the castings of this invention is that of an alloy of carbon with the aforesaid metallic substances to be understood as existing.

109812/1307

Claims (4)

Patent claims: 1. Cast body made of refractory melt casting compound, characterized by a content of at least 5 wt .-% of free Carbon, which essentially penetrates randomly oriented metal carbide crystals and locks them together, and the following analytical composition: a.) carbon; b) at least 20% by weight of one of the following metal carbide-forming agents Substances: titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, mixtures of these Metals and mixtures of these metals with at least one of the following metals: silicon, manganese, iron, cobalt or nickel, the content of the former metal carbide-forming Substances does not fall below 10% by weight; c.) 0 to 15% by weight of at least one diluent, namely at most 10% by weight of oxygen and at most 10% by weight of nitrogen, and
d.) the remainder, if any, of 0 to 5% by weight impurities. 2. Cast body according to claim 1, characterized in that the free carbon as a random and incoherent There is an intermediate structure. 3. Cast body according to claim 1 or 2, characterized in that the amount of free carbon is at least 11 wt .-% amounts to. 4. Cast body according to one of the preceding claims, characterized in that it contains the metal carbide-forming substance contains in an amount of at least 40% by weight. 109812/1307 5 · A method for producing a cast body according to the preceding claims, characterized in that a carbon-supplying Material with a metal carbide-forming material that is made up of the elemental metals and their alloys or oxides and / or the corresponding metal carbides, heated in a furnace to form a substantial part of the raw material to melt and a conversion between the metal carbide-forming Material and the carbon, taking into account the composition of the raw material, the nature of the atmosphere in contact therewith and the heating time and temperature selected so that the molten mass an analytical composition according to claim 1, and that the molten mass is in a casting mold to form a cast body solidifies, in which at least 5 wt .-% free Carbon essentially randomly oriented metal carbide crystals pressed and locked together. For: Corning Glass Works (Dr H.J. Wolff) Lawyer 109812/1307 Blank page